#include <stdio.h>
int main() {
    int a = 10;   // 00000000 00000000 00000000 00001010
    int b = 20;   // 00000000 00000000 00000000 00010100
    a = a ^ b;    // 00000000 00000000 00000000 00011110 -> 2 4 8 16 -> 30
    b = a ^ b;  // b = a ^ b ^ b   b = 30 ^ b  00000000 00000000 00000000 00001010 -> 10
    a = a ^ b;  // a = a ^ a ^ b   a = 30 ^ 10  00000000 00000000 00000000 00010100 -> 20
    printf("%d\n",a);
    printf("%d\n",b);
    return 0;
}